KISSIMMEE, Fla. -- Jonathan Singleton's bases-clearing triple was the highlight of a five-run seventh inning that allowed the Astros to come from behind and beat the Nationals, 6-4, on Monday night at Osceola County Stadium.

Singleton, the Astros' top prospect, shot a triple to center to score three runs and tie the game, and an RBI single by Trevor Crowe gave the Astros the lead. Matt Dominguez followed with an RBI double. All the runs were charged to Craig Stammen.

"I was just looking for a good pitch to hit over the middle part of the plate, and he came through with a fastball that caught a lot of the plate and I tried to put a good swing on it," Singleton said. "You always want to shine when they give you an opportunity."

The Nationals' Bryce Harper kept his hot streak going by hitting singles in three at-bats to raise his spring average to .459.

Washington starter Chris Young allowed two hits and one unearned run and struck out two batters while throwing 61 pitches over four innings. In 16 innings this spring, he's allowed 11 hits, four earned runs, seven walks and struck out nine.

Harper's RBI single in the third put the Nats ahead, 1-0, and Wilson Ramos made it 2-0 with an RBI single in the fourth. After Washington scored a run on a Ryan Zimmerman double play, Adam LaRoche's second homer in as many games made it 4-1.

Harper dropped a Justin Maxwell fly ball in left field with two outs in the fourth inning, allowing Fernando Martinez to score from first base on an error.

Astros starter Alex White, who's made the club but is trying to win a spot in the rotation, worked five innings and allowed nine hits and four earned runs. White has allowed 15 earned runs in 19 2/3 innings this spring for a 6.87 ERA.

Up next: Right-hander Brad Peacock, who found out Monday he made the Astros' Opening Day roster for the first time in his career, will audition for the fourth spot in the rotation when he faces the Yankees in Tampa, Fla., at 6:05 p.m. CT on Tuesday. Peacock is battling with White for the rotation spot. The game will be on MLB.TV and MLB Network.